You speak of the phenomenon of "knowledge filtration" among archaeologists and the drastic ways in which this process manifests itself. Please provide specific examples.

In the last century, a gold rush erupted in California. Prospectors dug tunnels into the hillsides. In these tunnels, buried in solid rock, they found human skeletal remains and hundreds of stone tools and weapons. Human bones and artifacts were found in early Eocene sediments. This would make them fifty million years old, while the prevailing view was that humans did not appear until one hundred or two hundred thousand years ago. The discoveries from the California gold mines were brought to the scientific world by Dr. J.D. Whitney, then California State Geologist. He described them in his book Geology of the Sierra Nevada, published in 1883 by the George Peabody Museum of Natural History at Harvard University. However, we hear little about these discoveries today. Why? Because of the aforementioned process of knowledge filtration. Dr. William B. Holmes, an anthropologist at the Smithsonian Institution in Washington, D.C., used his influential position in American science to

to conceal discoveries from the California gold mines. He wrote: "If Professor Whitney fully appreciated the account of human evolution as it is now understood, he would seriously consider jumping to the conclusions he has presented." This is one example of knowledge filtration.